U.S. patent application number 09/793452 was filed with the patent office on 2002-08-29 for roll arming sensor.
Invention is credited to Kastura, John L..
Application Number | 20020117385 09/793452 |
Document ID | / |
Family ID | 25159944 |
Filed Date | 2002-08-29 |
United States Patent
Application |
20020117385 |
Kind Code |
A1 |
Kastura, John L. |
August 29, 2002 |
Roll arming sensor
Abstract
A roll arming sensor is provided for determining an arming
signal for use on a vehicle for rollover detection. The roll arming
sensor includes a light source for generating a light beam and a
receiver for detecting the light beam. Disposed substantially
horizontal between the light source and receiver are first and
second cylindrical members, both oriented substantially parallel to
the longitudinal axis of the vehicle. The first and second
cylindrical members each have a window extending therethrough for
passing the light beam during normal vehicle travel. Each of the
first and second cylindrical members are movable to a second
position upon experiencing an armed condition, such as a roll
event, to prevent the optical beam from passing to the receiver,
thereby generating an arming signal for use with a rollover
sensor.
Inventors: |
Kastura, John L.; (Kokomo,
IN) |
Correspondence
Address: |
ROBERT M. SIGLER
DELPHI TECHNOLOGIES, INC.
Legal Staff, Mail Code: A-107
P.O. Box 9005
Kokomo
IN
46904-9008
US
|
Family ID: |
25159944 |
Appl. No.: |
09/793452 |
Filed: |
February 27, 2001 |
Current U.S.
Class: |
200/61.45R |
Current CPC
Class: |
H03K 17/968 20130101;
H01H 35/02 20130101 |
Class at
Publication: |
200/61.45R |
International
Class: |
H01H 035/02 |
Claims
1. An electromechanical roll arming sensor comprising: a housing
defining a first cavity; a source for generating a signal beam; a
receiver for detecting the signal beam: a first cylindrical member
disposed substantially horizontal within the first cavity between
the source and the receiver and having a window extending
therethrough, wherein said first cylindrical member is located in a
first position during a non-armed condition such that the signal
beam passes through the window, and said first cylindrical member
is movable to a second position during an armed condition such that
the signal beam is prevented from passing through the window to the
receiver; and an output for generating an arming signal when said
signal beam is prevented from passing to the receiver.
2. The roll arming sensor as defined in claim 1, wherein said
signal beam comprises an optical light beam.
3. The roll arming sensor as defined in claim 2, wherein said
source comprises a light emitting diode and said receiver comprises
a phototransistor.
4. The roll arming sensor as defined in claim 1, wherein said first
cylindrical member moves to the second position during a roll event
exceeding an angular threshold.
5. The roll arming sensor as defined in claim 1, further comprising
a second cylindrical member disposed substantially horizontal
within a second cavity in said housing between said source and said
receiver and having a window for allowing said signal beam to pass
therethrough, wherein the second cylindrical member is located in a
first position during a non-armed condition such that the signal
beam passes through the window, and said second cylindrical member
is movable to a second position during an armed condition such that
the signal beam is prevented from passing through the window.
6. The roll arming sensor as defined in claim 1, wherein said
second cylindrical member is biased by a bias spring to detect
vertical forces.
7. The roll arming sensor as defined in claim 1, wherein said roll
arming sensor is located on a vehicle to detect a potential
roll-over condition of the vehicle.
8. The roll arming sensor as defined in claim 7, wherein said roll
arming sensor generates an arming signal for use with a vehicle
rollover sensor.
9. The roll arming sensor as defined in claim 1 wherein said first
cylindrical member detects when said sensor exceeds a roll angle
greater than about thirty degrees relative to a gravity vector.
10. An electromechanical arming sensor for use in determining an
arming signal for rollover detection about a longitudinal axis of a
vehicle, said sensor comprising: a housing defining a first cavity;
a light source for generating a light beam; a receiver for
detecting the light beam: a first cylindrical member disposed
substantially horizontal within the first cavity and oriented
substantially parallel to the horizontal axis of the vehicle,
wherein said first cylindrical member is located between the source
and receiver and having a window extending therethrough for passing
the light beam during a non-armed driving condition, and said first
cylindrical member is movable to a second position during an armed
driving condition to prevent the light beam from passing to the
receiver; and an output for generating an arming signal when the
first cylindrical member moves to the second position.
11. The arming sensor as defined in claim 10, wherein said light
source comprises a light emitting diode and said receiver comprises
a phototransistor.
12. The arming sensor as defined in claim 10, further comprising a
second cylindrical member disposed substantially horizontal within
a second cavity in said housing between said light source and said
receiver, wherein said second cylindrical member includes a window
for allowing said light beam to pass therethrough when the second
cylindrical member is in a first position during a non-armed
driving condition, and preventing said light beam from passing to
said receiver when the second cylindrical member is in a second
position during an armed driving condition.
13. The arming sensor as defined in claim 12, wherein said second
cylindrical member is biased by a spring to detect vertical
forces.
14. The arming sensor as defined in claim 10, wherein said first
cylindrical member moves to the second position during a roll event
that exceeds an angular threshold
15. An electromechanical roll arming sensor comprising: a housing
defining a first cavity and a second cavity; a source for
generating a signal beam; a receiver for detecting the signal beam:
a first cylindrical member disposed substantially horizontal within
the first cavity between the source and receiver and having a first
window extending therethrough, wherein said first cylindrical
member is located in a first position during a non-armed condition
so that the signal beam passes through the first window, and said
first cylindrical member is movable to a second position during an
armed condition to prevent the signal beam from passing to the
receiver; a second cylindrical member disposed substantially
horizontal within the second cavity between the source and the
receiver and having a second window extending therethrough, wherein
said second cylindrical member is located in a first position
during a non-armed condition so that said signal beam is able to
pass through the second window, and the second cylindrical member
is movable to a second position during an armed condition to
prevent the signal beam from passing to the receiver; and an output
for generating an arming signal when said signal beam is prevented
from passing to the receiver during an armed condition.
16. The roll arming sensor as defined in claim 15, wherein said
signal beam comprises an optical light beam.
17. The roll arming sensor as defined in claim 16, wherein said
source comprises a light emitting diode and said receiver comprises
a phototransistor.
18. The roll arming sensor as defined in claim 15, wherein said
first cylindrical member moves to the second position during a roll
event exceeding an angular threshold, and said second cylindrical
member detects a free-fall condition.
19. The roll arming sensor as defined in claim 15 further
comprising a bias spring for biasing the second cylindrical member
to detect a free-fall condition.
20. the roll arming sensor as defined in claim 15, wherein said
roll arming sensor generates an arming signal for use with a
vehicle rollover sensor.
Description
TECHNICAL FIELD
[0001] The present invention generally relates to roll (tilt)
sensors and, more particularly, to an electromechanical roll arming
sensor, particularly for use in arming devices for deployment of
occupant protection devices upon detecting a potential rollover
condition for a vehicle.
BACKGROUND OF THE INVENTION
[0002] Automotive vehicles are increasingly employing
safety-related devices that deploy in the event that the vehicle
experiences a rollover so as to provide added protection to the
occupants of the vehicle. For example, upon detecting an
anticipated vehicle rollover condition, a pop-up roll bar can be
deployed such that, when activated, the roll bar further extends
vertically outward to increase the height of support provided by
the roll bar during a rollover event. Other controllable features
may include actuating deployment of one or more airbags, such as
front and side airbags, or actuating pretensioners to pretension
restraining devices, such as seatbelts or safety harnesses, to
prevent occupants of the vehicle from ejecting from the vehicle or
colliding with the roof of the vehicle during a rollover event.
[0003] In the past, mechanical-based rollover sensors have been
employed in automotive vehicles to measure the angular roll
position of the vehicle from which a rollover condition can be
determined. The mechanical sensors have included the use of a
pendulum normally suspended vertically downward due to the Earth's
gravitational force. Many mechanical automotive sensing devices are
employed simply to monitor the angular position of the vehicle
relative to a level ground horizontal orientation. As a
consequence, the basic automotive vehicle rollover sensors have
generally been susceptible to error when the vehicle travels around
a corner or becomes airborne, in which case the Earth's
gravitational force, which the sensor relies upon, may be overcome
by other forces.
[0004] More sophisticated rollover sensing approaches have been
considered which employ a plurality of sensors, a microprocessor
for processing the sensed signals according to one or more software
algorithms, and communication lines between the microprocessor and
deployable devices. Such approaches require as many as six sensors,
including three accelerometers and three angular rate sensors. The
three accelerometers generally provide lateral, longitudinal, and
vertical acceleration measurements of the vehicle. The three
angular rate sensors, also referred to as gyros, measure pitch
rate, roll rate, and yaw rate.
[0005] In commercial applications, many sophisticated rollover
sensing approaches also employ a safing device, such as an arming
sensor, to provide an independent verification of an actual
rollover event and prevent inadvertent deployment of devices due to
a possible failure of any of the sensors, the microprocessor, the
software algorithms, and the signal communication lines.
Conventional arming sensors have included the use of a Schmidt tilt
switch which employs a tilting cone vertically disposed relative to
the vehicle and aligned with the vertical gravity vector. An
optical light beam is generated by an infrared diode. An optical
path formed within the tilting cone is aligned to allow the light
beam to travel from the infrared diode to a phototransistor during
normal vehicle travel. Upon experiencing a sufficient roll angle or
roll rate, the tilting cone tilts relative to the vertical
orientation to prevent the light beam from passing to the
phototransistor, thereby generating an arming signal for use in
allowing a rollover deployment to occur.
[0006] While the use of a Schmidt tilt switch as an arming sensor
has served satisfactorily for some applications, this type of
conventional arming sensor is susceptible to some false arming
conditions. For example, the conventional tilt switch is generally
responsive to non-roll forces, such as those caused by vehicle
braking (deceleration) and those experienced during a free-fall of
the vehicle, which may occur during normal routine driving with
little or no possibility of a rollover. In addition, some
conventional arming sensors are generally expensive.
[0007] Accordingly, it is therefore desirable to provide for an
affordable and accurate roll arming sensor for arming devices for
deployment upon detecting a rollover event for a vehicle. More
particularly, it is desirable to provide for a roll arming sensor
that is affordable and accurate for detecting when the vehicle
experiences a minimum roll angle that is sufficient to serve as an
arming signal.
SUMMARY OF THE INVENTION
[0008] In accordance with the teachings of the present invention, a
roll arming sensor is provided. The roll arming sensor includes a
housing defining a first cavity, a source for generating a signal
beam, such as a light emitting diode, and a receiver for detecting
the signal beam. A first cylindrical member is disposed
substantially horizontal within the first cavity and between the
source and receiver. When used on a vehicle, the first cylindrical
member is oriented substantially parallel to the longitudinal axis
of the vehicle and is configured to roll substantially
perpendicular to the longitudinal axis of the vehicle upon
experiencing a sufficient roll angle. The first cylindrical member
has a window extending therethrough and is located in a first
position during a non-armed condition such that the signal beam
passes through the window. The first cylindrical member is movable
to a second position during an armed condition. In the second
position, the window is positioned to prevent the signal beam from
reaching the receiver, thereby generating an arming signal at an
output.
[0009] Accordingly, the present invention advantageously provides
for a cost effective roll arming sensor that achieves enhanced
reliability. The roll arming sensor is particularly useful for
arming one or more devices for deployment by a rollover detection
apparatus for use in a vehicle.
[0010] These and other features, advantages and objects of the
present invention will be further understood and appreciated by
those skilled in the art by reference to the following
specification, claims and appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The present invention will now be described, by way of
example, with reference to the accompanying drawings, in which:
[0012] FIG. 1 is a block diagram of a vehicle employing a rollover
sensor and a roll arming sensor;
[0013] FIG. 2 is a cross-sectional view taken through the central
longitudinal axis of a roll arming sensor according to the present
invention;
[0014] FIG. 3A is a cross-sectional view taken through lines
III-III in FIG. 2 illustrating the first cylindrical member of the
roll arming sensor in a non-armed position;
[0015] FIG. 3B is a cross-sectional view taken through lines
III-III in FIG. 2 illustrating the first cylindrical member of the
roll arming sensor in several armed positions;
[0016] FIG. 4A is a cross-sectional view taken through lines IV-IV
in FIG. 2 illustrating the second cylindrical member of the roll
arming sensor in a non-armed position; and
[0017] FIG. 4B is a cross-sectional view taken through lines IV-IV
in FIG. 2 illustrating the second cylindrical member of the roll
arming sensor in an armed position.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0018] Referring to FIG. 1, a rollover sensing module 12 and roll
arming sensor 20 are illustrated for use in generating a rollover
deployment signal 16 for deploying one or more devices upon
detecting an anticipated overturn (e.g., rollover) event for a
vehicle 10. The rollover sensing module 12 and roll arming sensor
20 of the present invention are preferably mounted on the
automotive vehicle 10 and oriented to detect, in advance, an
anticipated future rollover condition of the vehicle and initiate
responsive action. A vehicle rollover condition, as described
herein in connection with the present invention, may include
side-to-side rotation of the vehicle about the longitudinal axis of
the vehicle, commonly referred to as a "vehicle rollover," and
back-to-front rotation about the lateral axis of the vehicle,
commonly referred to as a "vehicle pitchover," or a combination of
rollover and pitchover. For purposes of describing the rollover
detection herein, the term "rollover" is generally used to refer to
either a rollover condition or a pitchover condition.
[0019] The rollover sensing module 12 may include a conventional
sensing module for sensing vehicle dynamics and detecting a
rollover condition of the vehicle. Upon detecting a vehicle
rollover condition, the rollover sensing module 12 provides an
output signal, which is indicative of the detected rollover
condition, to one input of a logic AND gate 14. The other input of
the logic AND gate 14 is coupled to the output of the roll arming
sensor 20. The logic AND gate 14 provides the rollover deployment
signal 16 when both the rollover sensing module 12 and the roll
arming sensor 20 produce outputs indicative of a possible vehicle
rollover event. The logic AND gate 14 may be implemented in analog
circuitry or via digital processing.
[0020] The rollover deployment signal 16 may be supplied to one or
more selected vehicle devices, such as a passenger air bag 18, or
other safety-related devices, to actuate the selected devices in
anticipation of an upcoming rollover event. In addition, the
rollover deployment signal 16 may be employed to deploy a pop-up
roll bar to provide extended lateral support to the occupants of
the vehicle just prior to the actual occurrence of the vehicle
rollover event. Similarly, the rollover deployment signal may
actuate an occupant restraining device, such as a seatbelt or
harness safety pretensioner, to eliminate slack in the restraining
device just prior to the vehicle rollover event occurring. Other
devices may likewise be controlled in response to the rollover
deployment signal 16.
[0021] Referring to FIG. 2, a roll arming sensor 20 is illustrated
therein in a cross-sectional view. Roll arming sensor 20 generally
includes a housing 22 defining a first cavity 32 and a second
cavity 42. The housing includes a dividing wall 52 disposed between
first and second cavities 32 and 42, respectively. Disposed within
the first cavity 32 is a first cylindrical member 30 which has a
cylindrical hole (window) 34 centrally formed therein along the
longitudinal axis of member 30. Disposed within the second cavity
42 is a second cylindrical member 40. The second cylindrical member
40 likewise has a cylindrical hole (window) 44 centrally formed
therein along the longitudinal axis of member 40. The first and
second cylindrical members are oriented substantially horizontal
relative to the ground plane.
[0022] The dividing wall 52 also has a cylindrical hole (window) 54
extending between the first and second cavities 32 and 42 and
located so as to align with the holes 34 and 44 of first and second
cylindrical members 30 and 40, respectively, when positioned in the
non-armed state. In addition, the bottom surface of dividing wall
52 has an inclined bottom edge 56. A bias spring 50 is disposed in
channels 38 and 48 below respective first and second cylindrical
members 30 and 40. The bias spring provides a bias force applied
vertically upward against second cylindrical member 40 to oppose
the force of gravity, thus reducing the total amount of downward
force applied to member 40. It should be appreciated that the
tapered bottom edge 56 of dividing wall 52 allows the bias spring
52 to extend to a raised vertical position.
[0023] The roll arming sensor 20 includes a light emitting diode
(LED) 24 disposed at one end of housing 22, within first cavity 32,
for generating an optical light beam. At the opposite end of
housing 22, within sealed cavity 42, is a phototransistor 26 for
sensing optical light. The LED 24 produces an optical light beam in
response to an input signal received at input 60. In the non-armed
state, the optical light beam passes through holes (windows) 34,
44, and 54 along the path shown by dashed line 28 and is received
and sensed at the phototransistor 26. The optical path 28 is
substantially parallel to the longitudinal axis of the first and
second cylindrical members 30 and 40. In addition, when detecting
roll about the longitudinal axis of a vehicle, the first and second
cylindrical members 30 and 40 are oriented substantially parallel
to the longitudinal axis of the vehicle. Phototransistor 26
generates an output signal in response to receiving the light beam.
The output signal is made available at output 62. According to one
embodiment, the output signal is a voltage signal that exceeds a
minimum threshold during a non-armed condition, and the voltage
signal is less than the minimum threshold upon detecting an armed
condition.
[0024] FIGS. 3A and 3B further illustrate the first cylindrical
member 30 of roll arming sensor 20 during a non-armed driving
condition and during armed driving conditions, respectively. In
FIG. 3A, the first cylindrical member 30 rests on a pair of
parallel mechanical stops 36a and 36b which position the first
cylindrical member 30 centered over channel 38 when the vehicle
roll angle is less than or equal to angle .alpha.. According to one
embodiment, angle .alpha. is equal to thirty degrees, so that when
the vehicle roll angle exceeds thirty degrees relative to a
horizontal plane, the first cylindrical member 30 is expected to
roll onto either angled surface 64a or angled surface 64b and into
an armed position such as is shown in FIG. 3B. In addition to
sensing a roll in excess of angle .alpha., the first cylindrical
member 30 may become elevated during a vehicle free-fall or
rollover such that it contacts the upper interior walls of the
first cavity 32. Whenever the cylindrical member 30 departs from
the initial non-armed position centered above channel 38 and moves
to an armed position against the side or upper interior walls of
first cavity 32, the hole 34 likewise moves to a new position so as
to block the light beam from passing between LED 24 and
phototransistor 26.
[0025] The second cylindrical member 40 is further illustrated in
FIGS. 4A and 4B during a non-armed condition and an armed
condition, respectively. As shown in FIG. 4A, the second
cylindrical member 40 rests on a pair of parallel mechanical stops
46a and 46b, which position the second cylindrical member 40
centered over channel 48. In addition, bias spring 50 provides a
bias force vertically upward from below second cylindrical member
40 so as to reduce the net amount of force applied downward due to
gravity. The bias spring 50 ensures that for a vehicle free-fall
situation, the cylinder member 40 is forced to a position where the
light path is broken. According to one embodiment, the bias spring
50 is designed so that when the combination of vertical
acceleration and gravity is less than 0.26 g the bias spring 50
will begin to move the second cylindrical member 40 vertically
upward. When this occurs, the second cylindrical member 40 moves
vertically upward towards the upper interior surface of cavity 42,
as shown in FIG. 4B, thereby displacing the hole 44 to an armed
position that blocks the passage of the optical light beam between
LED 24 and phototransistor 26.
[0026] The use of the first cylindrical member 30 advantageously
detects the presence of vehicle roll beyond angle .alpha., but the
position of the first cylindrical member is indeterminate for a
vehicle free-fall. The use of the second cylindrical member 50
biased by bias spring 50 advantageously allows for the detection of
the vehicle moving in a free-fall motion. It should be appreciated
that when the vehicle returns to a normal driving condition in
which the vehicle is at an angle of less than angle .alpha. (e.g.,
thirty degrees) and the vehicle is not experiencing a free-fall
driving motion, the first and second cylindrical members 30 and 40
will return to the normal non-armed positions as shown in FIGS. 3A
and 4A.
[0027] Accordingly, the electromechanical roll arming sensor 20 of
the present invention detects vehicle events, such as a vehicle
roll angle (tilt), beyond a threshold angle, or free-fall events,
during which certain deployment devices are armed ready to deploy
in the event that an anticipated rollover event is determined. This
allows for a redundancy check prior to deploying safety-related
devices on a vehicle. The roll arming sensor 20 provides an
independent verification of an actual roll event to prevent
inadvertent deployment due to failure of the rollover sensor(s),
processing unit, software algorithms, or communication lines. It
should be appreciated that the roll arming sensor 20 of the present
invention provides enhanced accuracy roll arming detection at low
cost.
[0028] It will be understood by those who practice the invention
and those skilled in the art, that various modifications and
improvements may be made to the invention without departing from
the spirit of the disclosed concept. The scope of protection
afforded is to be determined by the claims and by the breadth of
interpretation allowed by law.
* * * * *